A simmering controversy over published research for the Diovan blood pressure drug sold by Novartis and researchers at a Japanese university is heating up. Several papers have already been retracted amid heightened scrutiny over a relationship between the drugmaker and the Kyoto Prefectural University of Medicine, The Mainichi reports. Three papers submitted by university researchers found Diovan, which is used to lower blood pressure, had more to offer. One paper, in particular, claimed the drug also reduced the risk of heart attacks and strokes, which Novartis used in its promotions. The study was published in 2009 and helped Diovan become a huge seller in Japan. In fact, sales reached $5.6 billion worldwide in 2011 before generics became available. However, there were problems with all three papers. As Nature notes, the Japanese Circulation Society last December retracted two papers, citing “serious errors in data analysis.” One paper found Diovan helped diabetics avoid heart disease, and the other claimed the drug could benefit high-risk patients with high blood pressure.